Trapezium

Medically reviewed by Healthline Medical Team on April 14, 2015

There are eight carpal bones in the human wrist. They are arranged in two rows. They are located between the metacarpals and the ends of the radius and ulna bones. The trapezium rests in the row closest to the metacarpals. The scaphoid is located directly behind it, and the trapezoid is located to its side. The trapezium has three contact surfaces. These surfaces provide articulation points with other bones. The superior surface faces an upward and medial direction. It articulates with the scaphoid. The inferior surface is oval in shape. It articulates with the first metacarpal bone. The medial surface has a concave upper facet, which articulates with the trapezoid bone. The trapezium also provides an origination point for the oppenens pollicis and abductor pollicis, which help move the thumb. Most of the muscular tissues attach to the trapezium's palmar surface. However, many ligaments also attach to its lateral surface, which is broad and rough. The dorsal surface of the trapezium is smooth. It does not serve as many functions as its counterparts.

CMS Id: 140829